1. Field of the Invention
The present invention relates generally to a piping support of a gas turbine steam cooled combustor and more particularly to a piping support so improved that even when the piping support is damaged by combustion vibration, etc., dropping thereof is prevented so as to avoid an intrusion of fractions into a turbine portion, thereby preventing an accident including gas turbine blades, etc.
2. Description of the Prior Art
FIGS. 5(a) and (b) show an example of a gas turbine steam cooled combustor to which piping supports in the prior art are applied, wherein FIG. 5(a) is a plan view, and FIG. 5(b) is a side view. In FIGS. 5(a) and (b), a tail tube 102 of the combustor comprises a combustion gas outlet 104, through which a high temperature combustion gas is supplied into a gas path of the gas turbine. The tail tube 102 also comprises a by-pass pipe connecting port 103 for taking air from a turbine cylinder and a steam piping 101 is disposed around the by-pass pipe connecting port 103. The steam piping 101 is a piping through which cooling steam is supplied from a steam supply port 105 into a cooling passage provided on an inner circumferential wall of the tail tube 102 of the combustor and, after having cooled the wall of the tail tube 102 and elevated of temperature, is recovered from a steam recovering port 106. The steam piping 101 is supported by piping supports 110, 111, 112 and each of the piping supports 110, 111, 112 is fixed to an outer wall of the tail tube 102 of the combustor.
FIGS. 6(a) to (c) show the piping support 110, wherein FIG. 6(a) is a front view as seen from arrows on line Dxe2x80x94D of FIG. 5(a), FIG. 6(b) is a plan view and FIG. 6(c) is a side view. In FIGS. 6(a) to (c), the steam piping 101 is supported such that the steam piping 101 is pinched between upper and lower clamps 121, 122 via a spacer 125 disposed around the steam piping 101. The upper and lower clamps 121, 122 are fastened together by bolts/nuts 123, 124 and the lower clamp 122 is fixed by welding to the outer wall of the tail tube 102 via a fitting member 122a. The present example is an example where the lower clamp 122 has its one end fitted with the fitting member 122a to thereby support the steam piping 101 at the one end.
FIGS. 7(a) to (c) show the piping support 111, wherein FIG. 7(a) is a front view seen from arrows on line Exe2x80x94E of FIG. 5(a), FIG. 7(b) is a plan view and FIG. 7(c) is a side view. In FIGS. 7(a) to (c), like FIGS. 6(a) to (c), the steam piping 101 is supported such that the steam piping 101 is pinched between upper and lower clamps 221, 222 via a spacer 225 disposed around the steam piping 101. The upper and lower clamps 221, 222 are fastened together by bolts/nuts 223, 224 and a central portion of the lower clamp 222 is fixed by welding to the outer wall of the tail tube 102 via a fitting member 222a. The present example is an example where the lower clamp 222 has its central portion fitted with the fitting member 222a to thereby support the steam piping 101 at the central portion.
FIGS. 8(a) to (d) show the piping support 112, wherein FIG. 8(a) is a front view seen from arrows on line Fxe2x80x94F of FIG. 5(a), FIG. 8(b) is a plan view, FIG. 8(c) is a side view and FIG. 8(d) is a bottom view. In FIGS. 8(a) to (d), the steam piping 101 is supported such that the steam piping 101 is pinched between upper and lower clamps 321, 322 via a spacer 325 disposed around the steam piping 101. The upper and lower clamps 321, 322 are fastened together by bolts/nuts 323, 324 and the lower clamp 322 is fixed by welding to the outer wall of the tail tube 102 via fitting members 322a, 322b joined together in an L-shape. The present example is an example where the fitting members 322a, 322b joined together in the L-shape are interposed to thereby support the steam piping 101.
As mentioned above, the conventional steam piping 101 is fixedly supported using the upper and lower clamps, spacer and bolts/nuts so as to defend against vibration, etc., wherein the lower clamp is fixed to the wall surface of the tail tube 102 via the fitting member 122a or 222a, or the fitting members 322a, 322b, selected corresponding to a curved surface of the tail tube 102.
In the conventional gas turbine steam cooled combustor as mentioned above, the steam piping for the cooling steam is provided on the wall surface of the tail tube to be supported such that the steam piping is fixed to the piping support and the piping support is fixed by welding to the wall surface of the tail tube. The piping support comprises the upper and lower clamps, both made in a C-shape, and the piping support is so constructed that the steam piping is pinched between the upper and lower clamps via the spacer. The upper and lower clamps are fastened together by the bolts/nuts and the piping support is fixed to the wall surface of the tail tube. While the gas turbine is operated, a combustion vibration occurs and in the piping support so constructed, there may be a case where the fixation of the fitting member is loosened and should the fitting member be damaged and detached from the wall surface of the tail tube or the bolts/nuts be loosened by vibration, for example, then the clamps may drop out from the piping so that fractions thereof may enter a turbine portion together with combustion gas and in such a case, there is a large possibility that the gas turbine will be seriously damaged with regard to the blades, etc.
In view of the mentioned problem in the prior art, it is an object of the present invention to provide a piping support of a gas turbine steam cooled combustor in which the piping support supporting a steam piping has a construction so improved that even when the piping support is damaged by combustion vibration of the combustor or the like, dropping of the piping support out from the steam piping is prevented, so as to avoid an intrusion of fractions of the piping support into a turbine portion to thereby prevent an accident concerning gas turbine blades, etc.
In order to achieve the object, the present invention provides the following.
A piping support of a gas turbine steam cooled combustor, characterized in that the piping support comprises a ring fitted around a steam piping so as to be fixed to each other and an outer fitting member formed in a U-shape so that the ring makes contact with an inner circumferential surface portion of the outer fitting member to be fixed to each other. The outer fitting member at both ends thereof opposite to the inner circumferential surface portion is fixed to a wall surface of a tail tube.
In the piping support of the present invention, the ring is fitted around the steam piping and the steam piping at the outer circumferential surface thereof is fixed to the ring by welding or the like. The ring at the outer circumferential surface thereof makes contact with the inner circumferential surface portion of the outer fitting member formed in the U-shape so as to be fixed to each other by welding or the like. Thus, the steam piping is supported to the wall surface of the tail tube via the ring and the outer fitting member. As the ring and the outer fitting member are fixed to each other, even when the outer fitting member is detached from the wall surface of the tail tube due to fatigue by combustion vibration or the like, the outer fitting member is supported by the steam piping via the ring and no case of the outer fitting member being dropped from the piping occurs. Hence, there arises no case of dropped fractions of the piping support coming into the gas path of the gas turbine and turbine blades and the like are prevented from being damaged.